This psalm is short and sweet; I doubt the reason why we sing it so often as we do is for the shortness of it; but, if we rightly understood and considered it, we should sing it oftener for the sweetness of it, especially to us sinners of the Gentiles, on whom it casts a very favourable eye. Here is, I. A solemn call to all nations to praise God (Psa 117:1). II. Proper matter for that praise suggested (Psa 117:2). We are soon weary indeed of well-doing if, in singing this psalm, we keep not up those pious and devout affections with which the spiritual sacrifice of praise ought to be kindled and kept burning.

There is a great deal of gospel in this psalm. The apostle has furnished us with a key to it (Rom 15:11), where he quotes it as a proof that the gospel was to be preached to, and would be entertained by, the Gentile nations, which yet was so great a stumbling-block to the Jews. Why should that offend them when it is said, and they themselves had often sung it, Praise the Lord, all you Gentiles, and laud him, all you people. Some of the Jewish writers confess that this psalm refers to the kingdom of the Messiah; nay, one of them has a fancy that it consists of two verses to signify that in the days of the Messiah God should be glorified by two sorts of people, by the Jews, according to the law of Moses, and by the Gentiles, according to the seven precepts of the sons of Noah, which yet should make one church, as these two verses make one psalm. We have here,

I. The vast extent of the gospel church, Psa 117:1. For many ages in Judah only was God known and his name praised. The sons of Levi and the seed of Israel praised him, but the rest of the nations praised gods of wood and stone (Dan 5:4), while there was no devotion at all paid, at least none openly, that we know of, to the living and true God. But here all nations are called to praise the Lord, which could not be applied to the Old Testament times, both because this call was not then given to any of the Gentile nations, much less to all, in a language they understood, and because, unless the people of the land became Jews and were circumcised, they were not admitted to praise God with them. But the gospel of Christ is ordered to be preached to all nations, and by him the partition-wall is taken down, and those that were afar off are made nigh. This was the mystery which was hidden in prophecy for many ages, but was at length revealed in the accomplishment, That the Gentiles should be fellow-heirs, Eph 3:3, Eph 3:6. Observe here, 1. Who should be admitted into the church - all nations and all people. The original words are the same that are used for the heathen that rage and the people that imagine against Christ (Psa 2:1); those that had been enemies to his kingdom should become his willing subjects. The gospel of the kingdom was to be preached to all the world, for a witness to all nations, Mat 24:14; Mar 16:15. All nations shall be called, and to some of all nations the call shall be effectual, and they shall be discipled. 2. How their admission into the church is foretold - by a repeated call to praise him. The tidings of the gospel, being sent to all nations, should give them cause to praise God; the institution of gospel-ordinances would give them leave and opportunity to praise God; and the power of gospel-grace would give them hearts to praise him. Those are highly favoured whom God invites by his word and inclines by his Spirit to praise him, and so makes to be to him for a name and a praise, Jer 13:11. See Rev 7:9, Rev 7:10.

II. The unsearchable riches of gospel-grace, which are to be the matter or our praise, Psa 117:2. In the gospel, those celebrated attributes of God, his mercy and his truth, shine most brightly in themselves and most comfortably to us; and the apostle, where he quotes this psalm, takes notice of these as the two great things for which the Gentiles should glorify God (Rom 15:8, Rom 15:9), for the truth of God and for his mercy. We that enjoy the gospel have reason to praise the Lord, 1. For the power of his mercy: His merciful kindness is great towards us; it is strong (so the word signifies); it is mighty for the pardon of mighty sins (Amo 5:12) and for the working out of a mighty salvation. 2. For the perpetuity of his truth: The truth of the Lord endures for ever. It was mercy, mere mercy, to the Gentiles, that the gospel was sent among them. It was merciful kindness prevailing towards them above their deserts; and in it the truth of the Lord, of his promise made unto the fathers, endures for ever; for, though the Jews were hardened and expelled, yet the promise took its effect in the believing Gentiles, the spiritual seed of Abraham. God's mercy is the fountain of all our comforts and his truth the foundation of all our hopes, and therefore for both we must praise the Lord.